Exacerbations of asthma requiring corticosteroids are treated with the same dose irrespective of the factor or factors responsible for the exacerbation. There is no specific dose but the general range is 0.5 mg/kg to 1 mg/kg. I believe clinically that the response is much greater in asthma if the dose is divided and not given as a single dose. The optimal administration time for efficacy may be approximately 3 pm and 5:30 pm in the afternoon for both inhaled and oral corticosteroids, as therapy at this time may maximize effect on airway eosinophils during the night, a time when the inflammation is likely the most intense (Pincus). A useful adage attributed to Dr. Thomas L Petty, previous Professor of Medicine at the University of Colorado Health Sciences Center and Emertius Professor of Medicine at National Jewish Medical and Research Center in Denver, concerning systemic corticosteroid administration in obstructive airway disease is that you should avoid being “too little, too late, too long”. In other words, initiate treatment promptly when needed at a dose sufficient (0.5 mg/kg) and do not maintain for too long a time. The use of high dose inhaled corticosteroids reduces the need for systemic treatment and allows shorter courses.
Your subsequent questions related to concentration of blood IgE and therapeutic use of corticosteroids. There is no specific IgE that determines the need for systemic corticosteroid in the treatment of asthma. I was not sure what specific values were mentioned in your question as IgE concentrations are expressed in units of IU/ml and ng/ml with one IU equivalent to approximately 2.3ng. The decision for systemic therapy of asthma is based upon clinical assessment and not on a specific concentration of IgE. In other words, there is no cut off value above which one should use systemic corticosteroids. In the treatment of allergic bronchopulmonary aspergillosis (ABPA), many clinicians do follow systemic IgE levels and initiate systemic corticosteroids when the level exceeds a specific value. The general diagnostic value of total IgE for ABPA is greater than approximately 417 IU/ml or 1000 ng/ml (Vlahakis). The level of IgE decreases variably with successful treatment. Following subsequent IgE levels may help in the decision to reinitiate corticosteroid therapy, with the value of a 100% increase in the lowest baseline value often used as the point at which systemic therapy is reinitiated. Thus, the decision to treat is based upon a doubling of the lowest baseline for each patient rather than a generally applied value.
Diagnosis and treatment of allergic bronchopulmonary aspergillosis.
Vlahakis NE, Aksamit TR
Mayo Clin Proc. 2001;76(9):930.
Allergic bronchopulmonary aspergillosis (ABPA) is an underdiagnosed pulmonary disorder in asthmatic patients and patients with cystic fibrosis. Its clinical and diagnostic manifestations arise from an allergic response to multiple antigens expressed by fungi, most commonly Aspergillus fumigatus, colonizing the bronchial mucus. The clinical course is one of recurrent exacerbations characterized by chest infiltrates evident on chest x-ray films and associated with cough, wheeze, and sputum production that usually respond to oral corticosteroid treatment. Specific immunologic and radiologic markers of disease include elevation of the total serum IgE levels, presence of aspergillus IgE antibodies, and the occurrence of central bronchiectasis. Long-term treatment with corticosteroids is often required for effective management. The adverse effects of chronic corticosteroid use have led to attempts at treatment with antifungal agents such as itraconazole. Itraconazole has been reported anecdotally to be effective, and evidence for its effectiveness in randomized trials is still accruing. Consideration should be given to its use as a corticosteroid-sparing agent or for treatment of patients in whom corticosteroid response is poor. The natural history and prognosis of ABPA are not well characterized but may be complicated by progression to bronchiectasis and pulmonary fibrosis. If ABPA is diagnosed and treated before the development of bronchiectasis and fibrosis, these complications may be prevented.
Further studies on the chronotherapy of asthma with inhaled steroids: the effect of dosage timing on drug efficacy.
Pincus DJ, Humeston TR, Martin RJ.
J Allergy Clin Immunol. 1997 Dec;100(6 Pt 1):771-4.
I hope this information is of some help to you and your patients.
All my best.
Dennis K. Ledford, MD, FAAAAI